Cell dynamics underlying oriented growth of the Drosophila wing imaginal disc

Natalie A Dye (1) , Marko Popović (2) , Stephanie Spannl (1) , Raphael Etournay (1, 3) , Dagmar Kainmüller (1, 4) , Suhrid Ghosh (1) , Eugene W Myers (1, 5) , Frank Jülicher (2, 5) , Suzanne Eaton (1, 6)

1 MPI-CBG - Max Planck Institute of Molecular Cell Biology and Genetics
2 MPI-PKS - Max Planck Institute for the Physics of Complex Systems
3 Génétique et Physiologie de l'Audition
4 Janelia Farm Research Campus
5 CSBD - Center for Systems Biology Dresden
6 BIOTEC - Biotechnologisches Zentrum - Biotechnology Center TU Dresden

Quantitative analysis of the dynamic cellular mechanisms shaping the Drosophila wing during its larval growth phase has been limited, impeding our ability to understand how morphogen patterns regulate tissue shape. Such analysis requires explants to be imaged under conditions that maintain both growth and patterning, as well as methods to quantify how much cellular behaviors change tissue shape. Here, we demonstrate a key requirement for the steroid hormone 20-hydroxyecdysone (20E) in the maintenance of numerous patterning systems in vivo and in explant culture. We find that low concentrations of 20E support prolonged proliferation in explanted wing discs in the absence of insulin, incidentally providing novel insight into the hormonal regulation of imaginal growth. We use 20E-containing media to observe growth directly and to apply recently developed methods for quantitatively decomposing tissue shape changes into cellular contributions. We discover that whereas cell divisions drive tissue expansion along one axis, their contribution to expansion along the orthogonal axis is cancelled by cell rearrangements and cell shape changes. This finding raises the possibility that anisotropic mechanical constraints contribute to growth orientation in the wing disc.

Mots clés: Proliferation; Ecdysone; Insulin; Imaginal disc; Culture

Domaines: Bio-Informatique, Biologie Systémique [q-bio.QM]; Biologie moléculaire; Organisation et fonctions cellulaires [q-bio.SC]

Natalie A Dye, Marko Popović, Stephanie Spannl, Raphael Etournay, Dagmar Kainmüller, et al.. Cell dynamics underlying oriented growth of the Drosophila wing imaginal disc. Development (Cambridge, England), 2017, 144 (23), pp.4406 - 4421. ⟨10.1242/dev.155069⟩. ⟨pasteur-01678565⟩